arXiv subjects

P. Cancio

Publications and source records attributed to P. Cancio.

3 recordsLinked to original sources

arXiv2010

Observing the intrinsic linewidth of a quantum-cascade laser: beyond the Schawlow-Townes limit

A comprehensive investigation of the frequency-noise spectral density of a free-running mid-infrared quantum-cascade laser is presented for the first time. It provides direct evidence of the leveling of this noise down to a white noise plateau, corresponding to an intrinsic linewidth of a few hundred Hz. The experiment is in agreement with the most recent theory on the fundamental mechanism of line broadening in quantum-cascade lasers, which provides a new insight into the Schawlow-Townes formula and predicts a narrowing beyond the limit set by the radiative lifetime of the upper level.

physics.optics↗

arXiv2010

Saturated-absorption cavity ring-down spectroscopy

We report on a novel approach to cavity-ring-down spectroscopy with the sample gas in saturated-absorption regime. This technique allows to decouple and simultaneously retrieve empty-cavity background and absorption signal, by means of a theoretical model that we developed and tested. The high sensitivity and frequency precision for spectroscopic applications are exploited to measure, for the first time, the hyperfine structure of an excited vibrational state of $^{17}$O$^{12}$C$^{16}$O in natural abundance with an accuracy of a few parts in $10^{-11}$.

physics.optics↗

arXiv2003

Precision frequency measurement of visible intercombination lines of strontium

We report the direct frequency measurement of the visible 5s$^2$ $^1$S$_0$-5s 5p$^3$P$_1$ intercombination line of strontium that is considered a possible candidate for a future optical frequency standard. The frequency of a cavity-stabilized laser is locked to the saturated fluorescence in a thermal Sr atomic beam and is measured with an optical-frequency comb-generator referenced to the SI second through a GPS signal. The $^{88}$Sr transition is measured to be at 434 829 121 311 (10) kHz. We measure also the $^{88}$Sr-$^{86}$Sr isotope shift to be 163 817.4 (0.2) kHz.

physics.atom-ph↗